N-terminal acetylation stabilizes N-terminal helicity in lipid- and micelle-bound α-synuclein and increases its affinity for physiological membranes

J Biol Chem. 2014 Feb 7;289(6):3652-65. doi: 10.1074/jbc.M113.512459. Epub 2013 Dec 12.


The Parkinson disease protein α-synuclein is N-terminally acetylated, but most in vitro studies have been performed using unacetylated α-synuclein. Binding to lipid membranes is considered key to the still poorly understood function of α-synuclein. We report the effects of N-terminal acetylation on α-synuclein binding to lipid vesicles of different composition and curvature and to micelles composed of the detergents β-octyl-glucoside (BOG) and SDS. In the presence of SDS, N-terminal acetylation results in a slightly increased helicity for the N-terminal ~10 residues of the protein, likely due to the stabilization of N-terminal fraying through the formation of a helix cap motif. In the presence of BOG, a detergent used in previous isolations of helical oligomeric forms of α-synuclein, the N-terminally acetylated protein adopts a novel conformation in which the N-terminal ~30 residues bind the detergent micelle in a partly helical conformation, whereas the remainder of the protein remains unbound and disordered. Binding of α-synuclein to lipid vesicles with high negative charge content is essentially unaffected by N-terminal acetylation irrespective of curvature, but binding to vesicles of lower negative charge content is increased, with stronger binding observed for vesicles with higher curvature. Thus, the naturally occurring N-terminally acetylated form of α-synuclein exhibits stabilized helicity at its N terminus and increased affinity for lipid vesicles similar to synaptic vesicles, a binding target of the protein in vivo. Furthermore, the novel BOG-bound state of N-terminally acetylated α-synuclein may serve as a model of partly helical membrane-bound intermediates with a role in α-synuclein function and dysfunction.

Keywords: Lipid-binding Protein; N-terminal Acetylation; Parkinson Disease; Post Translational Modification; Protein Aggregation; Synuclein; α-Synuclein.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Glucosides / chemistry*
  • Humans
  • Membranes, Artificial*
  • Micelles*
  • Models, Molecular*
  • Protein Stability
  • Protein Structure, Secondary
  • Sodium Dodecyl Sulfate / chemistry*
  • alpha-Synuclein / chemistry*


  • Glucosides
  • Membranes, Artificial
  • Micelles
  • SNCA protein, human
  • alpha-Synuclein
  • octyl-beta-D-glucoside
  • Sodium Dodecyl Sulfate